Fire retardant roofing adhesive spreader

Abstract

A built-up roofing structure (10) is provided which is characterized by low dead weight, enhanced fire retardancy, and ease of construction. The structure (10) includes a lowermost deck (12) with integrated, insulative sections (24) applied thereover an adhered in place by a novel fire retardant mastic (27); the sections (24) each include a preformed expanded foam layer (14) covered by a roofing board (16). A modified bitumen membrane (18) is applied over and completes the roofing structure (10). The improved mastic includes asphalt, low volatility mineral spirits and a fire retardant additive such as an intumescent glass, and particularly a borosilicate glass. The mastic is advantageously applied using a spreader apparatus (30) having an elongated, tubular, apertured mastic delivery bar (32, 58) and a spreader means (46, 62) with a plurality of separate, spaced apart, lightweight trailing spreader chains (48).

We claim: 
     
       1. Apparatus for evenly spreading a flowable roof mastic, comprising: a source of flowable roof mastic;   an applicator separate from said source of mastic and consisting essentially of an elongated, hollow handle and an elongated, hollow mastic delivery bar, said handle having one end thereof for connection to said source of flowable roof mastic, said handle and bar being adapted to be transversely pulled across a roofing surface and said bar having structure defining a plurality of mastic delivery openings therethrough along the length of the bar;   an elongated mastic conveying line communicating with and operatively interconnecting said one end of the handle and said separate source of flowable roof mastic, with a mastic delivery pump interposed in said line; and   means for evenly spreading mastic from said openings including a plurality of chains operatively disposed relative to said bar and aligned with the openings to contact and spread mastic delivered therefrom as the bar is pulled,   each of said chains having an inner and an outer end, the inner end of each of the chains being operatively coupled with said delivery bar, with the outer end of each of the chains being free and independently movable relative to the ends of the remaining chains, for permitting the chains to conform to an irregular surface to be coated.   
     
     
       2. Apparatus as set forth in claim 1, including a chain draw bar moveable with the delivery bar and generally parallel with and spaced from said delivery bar, said chains being secured to said draw bar. 
     
     
       3. Apparatus as set forth in claim 1, at least certain of said openings having the axes thereof oblique to the longitudinal axis of the delivery bar for cooperatively applying mastic to an upraised rib of a roofing surface. 
     
     
       4. Apparatus as set forth in claim 1, including a tubular, generally U-shaped supply header having a length less than that of said delivery bar, said header being operatively coupled and in communication with the delivery bar for supplying mastic thereto.